1. Field of the Invention:
This invention relates to an improvement on the caliper carrying structure of a pin-slide type disc brake.
2. Description of the Prior Art:
A brake device must have an extremely high degree of reliability for braking a vehicle. In a so-called floating type disc brake, a caliper which straddles the periphery of a disc has a mutually confronting parts disposed on both sides of the disc. In one of the confronting caliper parts, there is provided a piston thrusting mechanism which pushes one of a pair of friction pads against the disc. The other friction pad is pushed against the disc by the other caliper part as it is caused to slide in the axial direction of the disc by a reaction to the pushing action of the piston thrusting mechanism. It is essential for such a floating type disc brake to always have smooth slidability.
To ensure such smooth slidability, the sliding parts of the brake must be prevented from rusting and protected from dust and the like by sealing them from the outside. In view of this requirement, there have been provided a variety of disc brakes of the pin-slide type the structure of which facilitates such sealing arrangement. The structural arrangement of the conventional pin-slide type disc brake is such that: There are provided slide pins. Each slide pin is secured either to a caliper or to a support and is arranged to slidably engage with an opening which is provided either in the support or in the caliper. Then, a bellows-like boot is arranged to cover the end of the opening and the outer circumferential part of the slide pin which is located outside of the opening. The brake thus permits sealing arrangement with a simple structure.
The brake device is attached to the body of a vehicle adjacent to the wheel and is not completely covered. Therefore, there is a high degree of probability that the boot is damaged by flying stones. Particularly, under a rough service condition such as frequent running on bad roads, there is a great possibility of having rain water or dust coming into the brake device through such a damaged part to cause insufficient sliding movement of the caliper and eventually to make the brake device inoperative due to rusting of the sliding parts thereof. A further improvement, therefore, has been necessary in the arrangement to keep a pin-slide type brake device smoothly slidable.